[Silicone Knowledge] Difference between HCR and LSR

Definition

HCR is high consistancy rubber for short and also called as solid silicone rubber or HTV. It is a kind of cellular polymer elastic material, with high temperature resistance, cold resistance, solvent resistance, adhesion resistance, electrical insulation, chemical properties and other characteristics.

LSR is Liquid silicone rubber for short. It is usually developed as a two-component product, with platinum / additional curing system. Compared with the solid silicone rubber, LSR has good fluidity, it is fast curing and more environmental-friendly, can completely meet the food contact requirements.

HCR and LSR Comparison

- Appearance

HCR is solid and has no fluidity.

LSR is in liquid form and has fluidity.

- Safety

HCR is a transparent material, and require to add curing agent during molding.

LSR a high transparent and food contact material. No vulcanizing agent and other auxiliary materials are added when molding.

- Processing

HCR should be firstly processed through two-roll mill mixing machine, cutting machine  to cut into a suitable size and thickness, then be put into the mold.

LSR is developed for liquid injection molding (LIM) , and can be processed with injection molding machines. Liquid injection molding simplifies the molding process: no need to mix the material in the milling machine, cutting and so on. The LSR is to be pumped into the injection mold by a dosing unit.

How to differentiate the products made of HCR and LSR

HCR product has low transparency, and usually comes with a smell of curing agent, but has no mark of injection gate on the body.

LSR products has high transparency, no odor, but has a mark of injection gate on the body.

Application

LSR is generally used in baby, kitchen products and medical supplies. After post curing (200℃ X 4 hours), it is more suitable to contact with food and human body.

Compared to LSR, it has much wider applications. HCR is generally used in daily necessities, industrial parts, automotive parts and other aspects.